(1) Field of the Invention
The present invention relates to a technique for receiving a resource obtainment request from a client terminal apparatus and obtaining a resource from a server apparatus via a network and transferring the resource to the client terminal apparatus via a network, in accordance with the request.
(2) Description of Related Art
Proxy server apparatuses, after receiving resource obtainment requests from client terminal apparatuses, obtain web contents (hereinafter referred to as resources) from web server apparatuses, substituting for the client terminal apparatuses that issued the resource obtainment requests.
FIG. 1 shows how resources are obtained via a conventional proxy server apparatus.
As shown in FIG. 1, client terminal apparatuses 11 and 12, a proxy server apparatus 21, and a web server apparatus 31 are connected to each other via networks.
The client terminal apparatus 11 is a personal computer including communicating devices such as: an input device such as a keyboard; an output device such as a display; a modem; and a router.
The client terminal apparatus 12 is a mobile telephone terminal apparatus that can be connected to the Internet. Because of downsizing and cost reduction, the capacity of a semiconductor memory of the client terminal apparatus 12 is small. The client terminal apparatus 12 does not include a magnetic recording medium.
The proxy server apparatus 21 is a computer that provides a proxy service, executing a proxy service program.
The web server apparatus 31 is a computer that provides a resource distribution service, executing a web service program. Note that the web server apparatus 31 stores a lot of resources in a recording medium therein in advance.
Note that the client terminal apparatus 11, proxy server apparatus 21, and web server apparatus 31 receive/transmit resources in compliance with HTTP (HyperText Transfer Protocol) shown in RFC (Request For Comments) 2616.
The client terminal apparatus 11 obtains a resource from the web server apparatus 31 via the proxy server apparatus 21, by executing the following steps (1) to (8).
(1) The client terminal apparatus 11 sends a resource obtainment request (hereinafter referred to as get request) to the proxy server apparatus 21.
The proxy server apparatus 21 (2) receives the get request from the client terminal apparatus 11, and (3) transfers the get request to the web server apparatus 31.
The web server apparatus 31 (4) receives the get request from the proxy server apparatus 21, (5) obtains a resource specified in the get request from the recording medium storing the lot of resources, and sends the obtained resource (hereinafter referred to as get response) to the proxy server apparatus 21.
The proxy server apparatus 21 (6) receives the get response from the web server apparatus 31, and (7) transfers the get response to the client terminal apparatus 11.
(8) The client terminal apparatus 11 receives the get response from the proxy server apparatus 21.
It should be noted here that the proxy server apparatus 21 stores the obtained get response in a recording medium therein for a certain period.
It is presumed here that the data transfer speed between the client terminal apparatus 11 and the proxy server apparatus 21 is ref erred to as client band and that the data transfer speed between the proxy server apparatus 21 and the web server apparatus 31 is referred to as server band.